Enhanced Inflation in the Dirac-Born-Infeld framework

Understand

We consider the Einstein equations within the DBI scenario for a spatially flat Friedmann-Robertson-Walker (FRW) spacetime without a cosmological constant.

• We derive the inflationary scenario by applying the symmetry transformations which preserve the form of the Friedmann and conservation equations.
• These form invariance transformations generate a symmetry group parametrized by the Lorentz factor $\ga$.
• We explicitly obtain an inflationary scenario by the cooperative effect of adding energy density into the Friedmann equation.